Koplik's spots (kop'liks) are small, irregular, red spots with a minute bluish white speck in the center of each seen on the buccal mucosa and lingual mucosa (mucous membrane of the inside of the cheek) and are pathognomonic of beginning measles. They are named after Henry Koplik (1858-1927), an American pediatrician who first described them in 1896.

They often appear a few days before the rash arrives and can be a useful sign to look for in children known to be exposed to the measles virus.

Eponymous medical signs